Production of tannic acids and extracts



UNITED STATES PATENT OFFICE.

IRANK LANG-FORD, 01

No Drawing.

To all whom. it may 00 cm'n lie it known that I. FRANK Iiarqorono, a citizen of the United States, residing at Eureka, in the county of l-Iumboldt and State of California, have inventednew and useful Improvements in the Production of Tannic Acids and Extracts, of which the following is a specification.

This invention relates to the production of tannins, tannic acids and other extracts from the wood of the alifornia redwood tree, Sequoia sempcnvz'rms, and to the use of such extracts in the refining and purifying treatment of aluminous clays and earths. The invention includes the use of sulfur compounds obtained from roasting aluminum sulfate in the extraction of the tannic acids from the wood of the Sequoia sempcm'z'rens.

In this invention, there is actually involved, it is now believed, the production of sulfuric acid through the interaction of tannins, and perhaps other substances of the wood, with the sulfur gases introduced in the presence of air and the contact surfaces of particles of the ore and the wood. Also it is believed that the aluminum of the ore or clay particles is attacked and dissolved by the sulfuric acid at the instant of formation or while in the nascent state. There 1s also involved the extraction of tannins and hydrocarbons from the wood, and cellulose fiber or altered wood pulp is produced. It is apparent also that soluble iron, alkalis and carbonates, and other fractional impurities of clays would in many cases go into solution before the dissolving of the aluminum compounds, and that if the process were stopped at this latter point a refined clay would be produced which would be suitable for refractories. If the process were stopped at an earlier stage there would be providedsulfotannates or some similar derivatives and probably very little of anything else in the extract. The use of alumi--' num sulfate for the production of the sulfurous gases for the process is also an important point. p

The invention includes the production of wood pulp from the redwood tree of California, Sequoia se'mpcr-oirens, and woods having similar sap, binder and tannin con tents, and pertains particularly to the use of the waste extracts obtained fromsuch wood and consists of agitating and leaching the EUREKA, CALIFORNIA.

PRODUCTION OF TANNIC ACIDS AND EXTRACTS.

Specification f Letters Patent Patented Sept. 13, 1921. Application filed October 2, 1917. Serial No. 194,331.

wood. bark or foliage of the redwood tree in water, a water solution of sulfurous acid or dilute sulfuric acid or sulfurous ases. or similar mineral acid to extract from the redwood pulp the staining. corroding acid sap, hydrocarbon compounds and tannins with which the cellulose fiber of the wood is combined, saturated or nature. The remaining cellulose fiber is suitable for pulping for wood pulp, or for wood products. the material having been first comminuted and then treated, or first treated and then comminuted, or employed as and left in the form of block wood. depending upon the products that are desired and the use contemplated for the extracts and the fiber or wood. The extraction process may be conducted with acids of different degrees of dilution, at different temperatures. and under different pressures above or bclow atmospheric pressure. and for different periods of time according to the conditions encountered.

The wood will give up to said acid solutions its acid sap, its tannins and its hydrocarbons and various binding elements separately and successively by varying the time of treatment, the strength of the acid. the quantity of the solution with respect to the quantity of the pulp, the pressure, or the temperature. Substances of various composition may be extracted. The fiber remaining will contain more or less of such substances as may be desired and will be improved in color and in structureand in durability, and will possess fire resisting properties and other qualities desirable in the further use of the wood. The invention provides substances containing tannin compounds or tannin deri atives useful and applicable to the tanning of leather, and to other uses such as the formation of tannates of iron, lime, sulfuric acid, and the like.

In the treatment of aluminous clays and earths it may be desirable to extract the acid sap and the tannins and some of the hydrocarbon binding substances of the wood together and to employ. this extract solution to saturate and wash clay, lateri'tc. bauxite. or other aluminous compounds to first purify them by unitinp or causing a reaction between the acid substance of the solution and the oxids, hydroxids, carbonates, sulfates or other compounds of iron, titanium, manganese, calcium, magnesium, so-

bound together in dium. potassium, sulfur. and the like that are common impurities of such aluminous ores and earths. The impurities are thus separated chemically and removed mechanically from the aluminous compounds of the ores. earths. and clays. This is accomplished by heating the mixture and agitating, settling. decanting. or filtering off the liquid from the solids and if desirable by washing the residue containing the aluminous compounds in hot water. depending upon the conditions and upon the products desired. For example. for the subsequent production of aluminum sulfate, alumina, or aluminum, I prefer to wash the aluminous residue thoroughly: while for the production of refractory materials, in some classes of material, I prefer to leave the aluminous residue saturated with the hydrocarbon and acid coinpounds contained in the extract solution. these acting in a beneficial way as a chemical and fuel agent in the subsequent heat treatment of burning of the refractory material.

In the treatment of aluminous ores, clays, laterites, and like earths with the redwood extract. it has been found that by using concentrated solutions and high temperatures near to or at the boiling point of the mass for a longer time than is required for extracting most of the impurities, the aluminous compounds will begin to be broken down and extracted or changed from a solid, like a silicate or hydroxid, to salts of aluminum having the characteristics of sulfates and sulfites, and this action which 'is undesirable for some uses of aluminous materials, such as for refractories. may be controlled or prevented by varying the duration of thetreatment and stopping the extraction process when aluminum begins to enter the solutions more than the impurities. lVhe n it is desired to extract the aluminum from such ores and materials, I prefer first to eliminate the impurities in the manner hereinbefore described and without roasting or calcining the crude material or the purified residue containing the aluminous silicate or other aluminous compound. Next,

this residue is mixed with finely comminuted redwood fiber or the extract therefrom, and into the slurry or liquid mixture, under pressure greater than one atmosphere, there is injected the sulfurous gases from burning pyrites or aluminum sulfate or alunite, or sulfur and the like. Then air is circulated through the mixture and it is heated possibly to dryness or even to ignition to bring about and to accelerate the reactions between the sulfur gases and the redwood extract and the clay or aluminous material and the formation of sulfates or sulfites. The aluminous compounds are changed, liberated, and enter into solution and the silica and insoluble portion drop out as residue upon dilutions with water, settling, tering.

I find that by the treatment of injecting sulfurous gases into the wet redwood mixture. the saps, tannins, and hydrocarbon compounds of the wood react with the sulfurous gases in the presence of aluminous earth and the wood fiber to promote the, formation of sulfuric acid, and that the aluminum and other soluble minerals of the clay or ore go into solution finally as sulfates, sulfites or similar combinations with sulfur, although complicated and obscure reactions take place leading up to this resalt.

The acid extracts from the redwood when filtered through clayey aluminum ores give up substances to the clay that burn at low temperatures and are entirely consumed apparently.

A wet mixture of the redwood pulp with clay or aluminous ore and sulfurous gases and air. heated, produces an extract that, separated from the sand and wood fiber residue and evaporated and heated. ignites at a low temperature and leaves a. residue of alumina, the tannin and wood extracts apparently acting as a fuel at this stage, supporting combustion and aiding in driving off completely the sulfur and some volatile impurities.

I find that aluminum silicates and hydrates like halloysite. alum clay, and rhyolite mud or ash that has been erupted at volcanic heat and deposited in water, whereby the extremely fine material has been segregated from the coarser in large deposits formed on the California coast sea margins,

decanting or filgive up their aluminum content and leave the silica as a residue by mixing with redwood pulp and water and injecting sulfur gases and applying heat and pressure, and that the necessary reactions and the solution of the aluminum compounds are accelerated by heating in or blowing in air, either hot or cold air.

The use of the term wood of the Sequoia scraper circus includes the use of the foliage. bark, or any other portion of the tree of that species.

What I claim is The process of extracting tannins and soluble wood substances from the wood of the Sequoia. scm-pmwire ns and other tannin b aaring woods, which process consists in mixing comminuted wood with pulverized aluminous earths. adding a moisteniug medium. injecting sulfur gases, injecting air, heating the mixture under pressure greater than atmospheric pressure, and leaching andseparating the liquid portion with the material taken up thereby from the insoluble residue.

In testimony whereof I aflix my signature.

FRANK LANGFORD. 

